1. Field of the Invention
The present invention relates to an optical pickup unit capable of reproducing data recorded on plural types of media such as HD DVDs (High Definition DVDs) (registered trade mark) or Blu-ray Discs (registered trademark) and of recording data onto plural types of media.
2. Description of the Related Art
FIG. 5 is a schematic diagram of one form of a conventional optical pickup unit.
An optical disk device is used to reproduce or record data such as information from/onto media. “Media” mean ones recording and mediating information or ones recording and transmitting information. One example of the media is an optical disk 700 such as a CD (Compact Disc) (trademark).
Current flows from a laser driver 510 to a laser diode 520. From the laser diode 520 a laser light (laser: Light Amplification by Stimulated Emission of Radiation) is outputted. The laser driver 510 acts as a laser driving circuit 510 for driving the laser diode 520 to cause the laser diode 520 to emit laser light. By the action of laser light emitted from the laser diode 520 as a result of supplying current from the laser driver 510 to the laser diode 520, information is recorded on the disk 700 or information recorded on the disk 700 is reproduced.
Laser light outputted from the laser diode 520 is applied to the disk 700 via a diffraction grating 530, an intermediate lens 540, a half-mirror 550, and an objective lens 560. The diffraction grating 530 is intended to split the laser light emitted from the laser diode 520 into several beams (not shown) by utilizing diffraction of light. The objective lens 560 serves to converge laser light into a signal portion 701 of the disk 700. Part of laser light reflected on the disk 700 returns to a photodetector 570, etc. When receiving light, the photodetector 570 converts the signal to an electrical signal to output a signal for operating a servo mechanism (not shown) of a lens holder (not shown) of an optical pickup unit 501. “Servo” or “servo mechanism” means a mechanism measuring the status of an object to be controlled and comparing the measurement with a reference value, for automatic correction control.
Part of laser light outputted from the laser diode 520 enters a front monitor diode 580. The front monitor diode 580 is intended to monitor laser light outputted from the laser diode 520 to perform feedback for controlling the laser diode 520. A housing (not shown), for example, is fitted with the laser driver 510, the laser diode 520, the diffraction grating 530, the intermediate lens 540, the half-mirror 550, the objective lens 560, the photodetector 570, and the front monitor diode 580. “Housing” means a box or box-like one enclosing components or constituent elements.
The laser driver 510, the laser diode 520, the photodetector 570, and the front monitor diode 580 are conductively connected to a flexible printed circuit 505. Description will be made of processes of fabricating the flexible printed circuit. A plurality of circuit conductors in the form of metallic foils such as copper foils are printed and juxtaposed on an insulating sheet. Protective layers are disposed on the circuit conductors to form the flexible printed circuit. The optical pickup unit 501 is configured as being provided with the above various elements. Although the optical pickup unit 501 is provided with other constituent elements than the shown ones, those constituent elements are not shown in FIG. 5 for convenience' sake. Laser light emitted from the laser diode 520 of the optical pickup unit 501 passes through the objective lens 560 and is applied to the optical disk 700 such as a CD loaded in a player body. By the action of laser light emitted from the laser diode 520, information is recorded in the optical disk 700 or information recorded in the optical disk 700 is reproduced. Information recording or reproduction is thus carried out in the optical disk device.
An example of the conventional optical pickup unit is an optical pickup not requiring a special variable diaphragm and applicable to all types of CDs (Compact Discs) and DVDs (Digital Versatile Discs). Such a conventional optical pickup unit is disclosed in e.g., Japanese Patent Application Laid-Open Publication No. 1999-224436 (pp. 1 and 3, FIG. 3).
Another example of the conventional optical pickup unit is an optical pickup unit and an optical disk device capable of realizing either thinning the device or miniaturizing the device even when the device is made to cope with lasers of various wavelength including blue laser. Such a conventional optical pickup unit is disclosed in e.g., Japanese Patent Application Laid-Open Publication No. 2005-32286 (pp. 1 and 3, FIG. 3).
Release was recently made of media of various standards such as “Blu-ray Disc” standard or “HD DVD” standard capable of higher-density recording than the conventional CD standard or DVD standard. The above conventional optical pickup unit 501 of FIG. 5 is however incapable of supporting a high-density recording optical disk such as Blu-ray Disc though it supports only the conventional optical disk 700 such as CD.
Media of the new standard, Blu-ray Disc standard incapable of serving the conventional standards but capable of high-density recording are considered as being of different standards from the DVD-standard media such as “HD DVD” and from CD-standard media. It has hitherto been considered difficult to develop a single optical pickup unit capable of supporting the above various media of quite different standards.
Conceived to cope with this was an optical disk device (not shown) having a plurality of optical pickup units capable of supporting a variety of media. One example thereof was an optical disk device provided with a first optical pickup unit (not shown) supporting Blu-ray Disc-standard media and with a second optical pickup unit (not shown) supporting both DVD-standard media and CD-standard media.
Such an optical disk device provided with a plurality of optical pickup units, the first optical pickup unit (not shown) supporting Blu-ray Disc-standard media and the second optical pickup unit (not shown) supporting both DVD-standard media and CD-standard media has however been considered to undergo possible deficiencies such as increase in the number of components resulting in increased size and weight as well as increased price.